The sensitivity of instantaneous coherence for considering elementary comparison processing. Part I: the relationship between mental activities and instantaneous EEG coherence

Schack, Bärbel; Grieszbach, G.; Krause, Werner

doi:10.1016/s0167-8760(98)00052-x

Cited by 35 publications

(19 citation statements)

References 22 publications

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“…The second characteristic is its wide coherence over the recorded channels. We must emphasize here that low frequencies are not themselves pathological; they occur as thalamocortical synchronization (21,22) continuously during ␦ sleep (20,23), and transiently during wakefulness, under specific conditions of mental and emotional activity (18,19,(24)(25)(26). Rather, we are dealing here with an ongoing low-frequency activity that is present during the entire day and that continuously modifies and limits the dynamic organization of the brain; it does so all the more efficiently because it produces large-scale coherence.…”

Section: Discussionmentioning

confidence: 98%

Thalamocortical dysrhythmia: A neurological and neuropsychiatric syndrome characterized by magnetoencephalography

Llinás

Ribary

Jeanmonod

et al. 1999

Proc. Natl. Acad. Sci. U.S.A.

1,232

1,093

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Spontaneous magnetoencephalographic activity was recorded in awake, healthy human controls and in patients suffering from neurogenic pain, tinnitus, Parkinson's disease, or depression. Compared with controls, patients showed increased low-frequency rhythmicity, in conjunction with a widespread and marked increase of coherence among high-and low-frequency oscillations. These data indicate the presence of a thalamocortical dysrhythmia, which we propose is responsible for all the above mentioned conditions. This coherent activity, the result of a resonant interaction between thalamus and cortex, is due to the generation of lowthreshold calcium spike bursts by thalamic cells. The presence of these bursts is directly related to thalamic cell hyperpolarization, brought about by either excess inhibition or disfacilitation. The emergence of positive clinical symptoms is viewed as resulting from ectopic ␥-band activation, which we refer to as the ''edge effect.'' This effect is observable as increased coherence between low-and high-frequency oscillations, probably resulting from inhibitory asymmetry between high-and low-frequency thalamocortical modules at the cortical level.edge effect ͉ activity ͉ ␥ activity ͉ humans

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Section: Discussionmentioning

confidence: 98%

Thalamocortical dysrhythmia: A neurological and neuropsychiatric syndrome characterized by magnetoencephalography

Llinás

Ribary

Jeanmonod

et al. 1999

Proc. Natl. Acad. Sci. U.S.A.

1,232

1,093

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“…247 To compute coherence we used a procedure developed by 248 Schack (Schack et al, 1999). A model-based parametric 249 approach based on autoregressive moving average models 250 (model orders p = 15 and q = 5) with time-varying parameters 251 (for details see also Schack and Krause, 1995).…”

mentioning

confidence: 99%

Synchronized brain activity during rehearsal and short-term memory disruption by irrelevant speech is affected by recall mode

Kopp

Schröger

Lipka

2006

International Journal of Psychophysiology

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EEG coherence as a measure of synchronization of brain activity was used to investigate effects of irrelevant speech. In a delayed serial recall paradigm 21 healthy participants retained verbal items over a 10-s delay with and without interfering irrelevant speech. Recall after the delay was varied in two modes (spoken vs. written). Behavioral data showed the classic irrelevant speech effect and a superiority of written over spoken recall mode. Coherence, however, was more sensitive to processing characteristics and showed interactions between the irrelevant speech effect and recall mode during the rehearsal delay in theta (4–7.5 Hz), alpha (8–12 Hz), beta (13–20 Hz), and gamma (35–47 Hz) frequency bands. For gamma, a rehearsal-related decrease of the duration of high coherence due to presentation of irrelevant speech was found in a left-lateralized fronto-central and centro-temporal network only in spoken but not in written recall. In theta, coherence at predominantly fronto-parietal electrode combinations was indicative for memory demands and varied with individual working memory capacity assessed by digit span. Alpha coherence revealed similar results and patterns as theta coherence. In beta, a left-hemispheric network showed longer high synchronizations due to irrelevant speech only in written recall mode. EEG results suggest that mode of recall is critical for processing already during the retention period of a delayed serial recall task. Moreover, the finding that different networks are engaged with different recall modes shows that the disrupting effect of irrelevant speech is not a unitary mechanism

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“…The coherency for congruent situation is higher than incongruent situation. [8] The higher coherency ranges from 0.8 -1 while mild coherency ranges from 0.6 -0.8. In the plots the series 1 is the average value of coherence for an incongruent situation while series 2 is the average value of coherence for a congruent situation.…”

Section: Coherencementioning

confidence: 99%

PSD based Coherence Analysis of EEG Signals for Stroop Task

Unde¹,

Shriram²

2014

IJCA

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The coherence analysis is based on spectral analysis, which describe the synchronization of electroencephalogram (EEG) rhythms between brain areas. Coherence analysis is a noninvasive technique for studying functional relationships between brain regions. The coherence analysis is a kind of study based on spectrum analysis, which can describe the coordination of the brain electric activities of different frequencies between brain areas. Aimed at the coherence analysis of EEG signal between brain areas using an activity Stroop Task. Power spectral density (PSD) has been used for the analysis of event related coordination of neurophysiological signals of neural responses for a particular task which the subject repetitively performs. The Welch method is used to study the PSD. we constructed simulated EEG data, looked for the suitable approach for cognitive EEG and tried to apply it to the EEG data from Stroop Tack. The result shows coherency of EEG signal of the brain areas for Stroop task activity.

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The sensitivity of instantaneous coherence for considering elementary comparison processing. Part I: the relationship between mental activities and instantaneous EEG coherence

Cited by 35 publications

References 22 publications

Thalamocortical dysrhythmia: A neurological and neuropsychiatric syndrome characterized by magnetoencephalography

Thalamocortical dysrhythmia: A neurological and neuropsychiatric syndrome characterized by magnetoencephalography

Synchronized brain activity during rehearsal and short-term memory disruption by irrelevant speech is affected by recall mode

PSD based Coherence Analysis of EEG Signals for Stroop Task

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